Intelligent efficient servo-actuator for a downhole pulser

Abstract

An improved energy efficient intelligent pulser driver used for generating a mud pulse in a MWD (measurement while drilling) application. In the pulser driver, a direct current (DC) powered control circuit activates a three-phase DC brushless motor that operates a servo-valve. Opening of the servo-valve equalizes pressure in a plenum causing the operation of a main valve reducing flow area and causing a pressure spike in the mud column. Closing of the servo-valve creates a reduction in mud pressure that operates the main valve and increases the flow area causing an end to the pressure spike. The servo-valve is powered both in opening and closing operations by the motor.

1 - 15 . (canceled) 
     
     
         16 . A servo-controller for use with a downhole measurement-while-drilling pulser actuator, the servo-controller comprising a sensor, memory, control circuitry, and an operator interface. 
     
     
         17 . The servo-controller of  claim 16  wherein the sensor is a mudflow sensor, pressure sensor, temperature sensor, rotation-step counter, position sensor, velocity sensor, current level sensor, battery voltage sensor, timer, or error monitor. 
     
     
         18 . The servo-controller of  claim 16  wherein the memory stores time-stamped or counted sensed events together with an event-type indication. 
     
     
         19 . The servo-controller of  claim 16  wherein the control circuitry is programmable to cause an action within the actuator responsive to a sensed event, a time, an elapsed time, a series of sensed events, or any combination thereof. 
     
     
         20 . The servo-controller of  claim 16  wherein the operator interface provides information from memory to the operator. 
     
     
         21 . The servo-controller of  claim 16  wherein the operator interface allows an operator to alter the programming of the control circuitry.